Boat stern vacuum relieving attachment



Dec. 20, 1955 DUNNING 2,727,486

BOAT STERN VACUUM RELIEVING ATTACHMENT Filed May 25, 1954 7 K 3 [NV/1N7()R. ,[uther 7. punni n6 ATTE] R N EYS United States Patent BOAT STERNVACUUM RELIEVING ATTACHMENT Luther T. Dunning, Norfolk, Va. ApplicationMay 25, 1954, Serial No. 432,106 Claims. (CL 114-67) This inventionrelates to devices for increasing efficiency of boats, and in particularmeans for relieving the vacuum or cavitation to the rear of the sternboard of a boat and between the bottom of the boat and the surface ofthe water.

The purpose of this invention is to provide means for supplying acurrent of air to an area to the rear of the stern board of a boat torelieve the pulling force resulting from the vacuum formed by waterrushing over the sides of the boat.

The rush of fluid over the sides of an object passing through the fluidevacuates the fluid and air from an area directly behind the objectcausing a vacuum or partial vacuum generally referred to as cavitationand this area provides a direct pulling force in the direction oppositeto that in which the object is traveling and as the power required tomove the object forwardly must be sufficient to overcome this force theefliciency of an engine or other driving power unit of a boat, airplaneor motor vehicle is reduced.

Various attempts have been made to supply currents of air to this area,however, all attempts to supply air to an area to the rear of a sternboard of a boat have not been successful because the air is not suppliedat the proper point.

With this thought in mind, this invention contemplates an auxiliarystern board spaced from and positioned to the rear of the conventionalstern board of a boat whereby an area is provided to the rear of theconventional stern board for the circulation of air and the presence ofa vacuum at the stern of a boat with the auxiliary stern board thereondraws air downwardly through the passages whereby the vacuum isrelieved.

The object of this invention is, therefore, to provide means for formingthe stern of a boat whereby the suction of a vacuum area following thestern board draws air through the stern board into the vacuum area.

Another object of the invention is to provide means for relieving thevacuum area following the stern board of a boat in which the relievingmeans is adapted to be attached to boats now in use.

A further object of the invention is to provide an attachment for thestern of a boat whereby vacuum following the stern is relieved in whichthe attachment is of a simple and economical construction.

With these and other objects and advantages in view, the inventionembodies a panel of substantially the same pattern as the stern board ofa boat with vertically disposed spacing cleats positioned on the forwardside of the panel and means for attaching the panel with the cleatsthereon to the stern board of a boat.

Other features and advantages of the invention will appear from thefollowing description taken in connection with the drawing, wherein:

Figure 1 is a side elevational view showing the hull of a boat with theauxiliary stern board mounted at the stern and with air currentsindicated by broken lines and arrows flowing between the auxiliary sternboard and conventional stern board whereby vacuum or cavitation at thestern of the boat is relieved.

Figure 2 is a cross section taken on line 2-2 of Figure 1 with the partsshown on an enlarged scale showing the cleats for mounting the auxiliarystern board positioned on the stern board of the boat.

Figure 3 is a plan view of the stern of the boat with the forwardportions thereof broken away showing the air circulating areas betweenthe stern board and auxiliary stern board.

Figure 4 is a detail showing a modification wherein an auxiliary sternboard is provided with openings spaced downwardly from the top of theboat.

Figure 5 is a view of the auxiliary stern board, taken on line 55 ofFigure 4.

Referring now to the drawing wherein like reference characters denotecorresponding parts, the vacuum relieving attachment of this inventionincludes a panel 10 substantially of the same size and pattern as thatof a stern board 11 of a boat 12 and cleats 13, 14 and 15 positionedbetween the panel 10 which provides an auxiliary stern board and thestern board 11.

As illustrated in Figure 3, the cleats are secured to the panel 10 withnails or other fasteners, as indicated by the numeral 16, and the panel10 with the cleats thereon is secured to the stern board 11 withfasteners such as nails or screws 17.

The lower ends of the cleats of the boat, are provided with beveledsurfaces 18 and 19, respectively, which facilitate circulation of airthrough areas 20 and 21 between the panel 10 and stem board 11.

The stern board 11 is connected to sides 22 and 23 and a bottom 24 of aboat by conventional means and, as illustrated in Figure 1, with theboat positioned in water, as indicated by the numeral 25, a lower edge26 of the panel 10 extends downwardly to the lower surface 27 of thebottom of the boat and with the boat traveling forwardly a vacuum area28 would be produced directly following the stern board and panel. Avacuum causes suction and with the vacuum surrounded by water thesuction would be directly applied to the lower ends of the passages 20and 21 whereby air, as indicated by the arrows 29, would be drawndownwardly through the passages 20 and 21 to fill the vacuum. By thismeans the vacuum is continuously relieved and the pulling forceresulting therefrom eliminated.

In the design shown in Figures 4 and 5 an auxiliary stern board 30,similar to the panel 10, and which isprovided with cleats 31, 32 and 33,is attached to a stern board 34 of a boat 35, and in this design theupper ends of air channels 36 and 37 between the conventional andauxiliary stern boards are sealed by a strip 38. The auxiliary sternboard 30 is provided with openings, as indicated by the numeral 39,whereby air is admitted to the channels 36 and 37 at points spaced belowthe upper end of the stern of the boat, as indicated by the arrows inFigure 4.

It will be understood that modifications, within the scope of theappended claims, may be made in the design and arrangement of the partswithout departing from the spirit of the invention.

What is claimed is:

l. A boat having a hull with side walls, a bottom and a stern board,means for providing open vertically positioned air circulating channelsterminating in a plane parallel with the bottom said openings beingadjacent to and parallel with the stern board.

2. A boat having a stern board with open vertically disposed aircirculating channels extended therethrough parallel therewith andterminating in a plane parallel with the lower end of the stern board.

13 and 15, at the sides 3. In a vacuum relieving attachment, thecombination which comprises a boat having a bottom, side walls and astern board and an auxiliary stern board spaced from and parallel withthe stern board of the boat and attached thereto providing openvertically disposed air circulating channels between the auxiliary sternboard and the stern board of the boat said openings terminating in aplane parallel with said bottom.

4. In a vacuum relieving attachment for a boat, the combination whichcomprises a boat having a hull with a bottom, side walls and a sternboard, an auxiliary stern board positioned parallel to and spaced fromthe stern board of the boat, vertically disposed cleats positionedbetween the auxiliary stern board and stern board of the boat providingspacing means curing the auxiliary stern board and cleats to the boat,said auxiliary stern board having openings therethrough and saidopenings being spaced from the upper end thereof.

5. In a vacuum relieving attachment for a boat, the

and suitable fasteners se- 15 combination which comprises a boat havinga hull with a bottom, side mails and a stern board, an auxiliary sternboard positioned parallel to and spaced from the stern board of theboat, vertically disposed cleats positioned between the auxiliary sternboard and stem board of the 1 boat providing spacing means and suitablefasteners securing the auxiliary stern board and cleats to the boat,said auxiliary stern board having openings therethrough and saidopenings beingsp'aced from the upper end thereof, the upper endsofopenings between the conventional and auxiliary ster-n boards beingclosed.

References Cited int-he file of this patent UNITED STATES rA'TENrs955,703 Settergren Apr. 19, 1910 1,005,698 Dillon Oct. 10, 19111,093,692 Gawley Apr. 21, 1914 2,188,183 Garment Nov. 15, 1949 2,619,065Brush Nov. 25, 1952

